1. Field of the Invention
The present teachings relate to control systems, or methods directed to the control of the charging of a lithium-ion battery system. Such methods can employ algorithms which consider various internal battery parameters or states to determine charging conditions.
2. Discussion of the Related Art
One known technique, as presented in U.S. Pat. No. 5,982,152, directed to primarily to Ni-MH batteries, estimates charging efficiency based on the battery temperature increment and stops the charging operation when the charging efficiency is less than certain value. This technique can prevent unnecessary charging. Unneeded charging does not increase battery's state of charge but can lead to possible deterioration of the battery.
Conventionally, battery performance deterioration is addressed by adding an excess of electrode material and restricting the usable battery range. Such an approach results in a heavier and more expensive battery.
Clearly, a need exists for a Li-ion battery charging control system that measures and determines significant internal battery states and parameters to control the charging system, which can in turn, lead to a lighter and less expensive energy storage device, particularly for automotive applications.